Gauge



travel combined with another and less active Patented Oct. 31', 1933 UNITEo rum;emery g 1 Joseph W. Motherwell, Melrosa Mas sl, assignor a to The Ashton Valve Company,

l Cambridge,

Mass, a-corporation of Massachusetts H 'Aipplication October 1, 1929. Serial No. 396,557 4 3 Claims. (01. rag-'10s) The principal object of my invention is to give a differential reading on a dial so that the pointer or indicator will move through a certain angular distance at one portion of the dial to indicate an increase of a unit of pressure and will move through a different angular distance atanother portion of the dial to indicate an equal increase of pressure.

A feature of my invention is a Bourdon tube to operate a pointer or indicator at a desired rate of Bourdon tube to operate at a desired position of the pointer to retard the speed of travel of the first Bourdon tube so as to indicate relatively greater increases of pressure per angular unitor" travel of the pointer.

. erate with the dial '14 shown in A particular feature of my invention is the use of a plurality of Bourdon tubes, one of which, at the desired point, operatively engages the re mainder to retard said remainder.

Other features will be pointed out below.

Inthe drawing Figurel is an elevation, partly in section, of a adjustable to engage portion 22 provided at the brazing, an activeBourdon tube 3 and an active Bourdon pressure tube 4, both communicating with passage 2. An active Bourdon pressure tube is one that is subjected to pressure and is responsive in movement to changes in pressure. The movable end of tube 4 is closed and has fixed to it a bracket 5 extending beneath the movable end of tube 3, the bracket being threaded internally (not shown) to engage screw 6 which is adjustable on bracket 5 and may be firmly held by check nut 'I. The movable end of tube 3 is closed and is provided with a suitable portion 8 to be engaged, when desired, by screw 6. To bracket 5 is pivoted one end of adjustable link 9, the other end being pivotally connected to one endo'f sector 10 which is suitably pivoted to a fixed portion of the device at 11. The toothed end of the sector engages pinion 12 fixed to shaft 13, said shaft carrying any suitable pointer or indicator 131 to coop- Figure 3, the dial and the mechanism so far described to be mounted in a suitable casing which it is not necessary to describe.

In using the form of my device shown in Figure '1 the screw 6 is adjusted as desired so as to endesired time. When pres- 2 first expands tube 4 the the dial in Figure 3 from angular distance for each degree of increase of pressure, This" continues until the screw 6 engages portion 8 when the tube 3 will retard the movement of the screw and of the sector and pointer so that the latter will move at a slower rate for each degree of increase of pressure and consequently the angular distance along the dial will be less for each such increase. In this way the dial is available to indicate pressure through such range as may be desired with gage'portion 8 at the sure through passage pointer will move along 0 to 30. moving a certain the spacing to indicate each. degree further apart and to the active tube .17. Tube 16 carries bracket 19 at its closed movable end, said bracket carrying screw 20and check nut 21-, the screw being closed movable end of tube 17, which acts at the desired time to retard and consequently to retard the movement of the pointer which is operated by tube 16 through mechanism which is substantially the same as the corresponding mechanism of Figure 1.

89 the movement'of tube 16 The tube 3'may have a relatively thick wall compared with the thickness of the wall of tube 4 and is therefore less active than tubef 4 and consequently the movable end of slowly than the movable end of tube 4 so that the tube 3 will move more screw to be carriedby tube 4 will, at the desired?" time, engage portion 8 with the result that tube 3 will retard the movement of tube 4.

Similarly in Figure 2 the tube 17 may have a relatively thick wall compared with the thickness of the wall-of tube 16.

It will be observedthatthe angular displacement of the pointer is directly proportional to the pressure applied to the more active element, such as tubes 4 and 16, until the adjustable screw en-,.100 gages the end of the less'active element, such as tubes 3 and 1'7, and thereafter the angular displacement of in proportion to the relative inactivity of the less active elements.

What I claim is:

1. A gauge comprising a dial; an indicator co operating with the-dial; an active Bourdon tube distance along said dial under a certain increase the pointer is uniformly retarded "tending to move said indicator a certain angular of pressure; and another active Bourdon tube, less active than the first-mentioned tube, and carrying a part to retardingly engage a part carried by the first-mentioned tube at a desired time so as to cause said indicator to move along said dial after said engagement a less angular distance than the first-mentioned distance under an increase 'of pressure equal to the first-mentioned increase.

2. A gauge comprising a dial; an indicator cooperating with the dial; an active Bourdon tube tending to move said indicator a certain angular distance along said dial under a certain increase of pressure; and another active Bourdon tube, less active than the first-mentioned tube, and carrying a part to retardingly engage a part carried by the first-mentioned tube at a desired time so as to cause said indicator to move along said dial after said engagement a less angular distance than the first-mentioned distance under an increase of pressure equal to the first-mentioned increase; and means to relatively adjust said parts.

3. A gauge comprising a dial; an indicator cooperating with the dial; an active Bourdon tube tending to move said indicator a certain angular distance along said dial under a certain increase of pressure; and another active Bourdon tube,

less active than the first-mentioned tube, one of said tubes carrying an adjustable screw and the other tube carrying a part to retardingly engage said screw at a desired time so as to cause said indicatorto move along said dial after said engagement a less angular distance than the firstmentioned distance under an increase of pressure equal to the first-mentioned increase.

JOSEPH W. MOTHERWELL. 

